The Subansiri Lower Dam, officially named Subansiri Lower Hydroelectric Project (SLHEP), is an under construction gravity dam on the Subansiri River in North Eastern India. It is located upstream of Subansiri River on Arunachal Pradesh. Described as a run-of-the-river project by NHPC Limited, the Project is expected to supply 2,000 MW of power when completed. The project has experienced several problems during construction to include landslides, re-design and opposition. It was expected to be complete in 2018. It is notable that, if completed as planned, it will be the largest hydroelectric project in India. As of early 2019, work was not progressing on either of the two major dam projects in the Assam region, the Dibang and the Lower Subansiri. After clearance of ‘Subansiri Lower Project’ by Hon’ble NGT vide its Order dated: 31.07.2019, Main works of the Dam has been resumed on 15.10.2019. Design The concrete gravity dam is designed to be tall, measured from the river bed and from foundation. Its length will be and the dam will have a structural volume of . The reservoir created by the dam will have a gross storage capacity of , of which can be used for power generation or irrigation. At normal level, the reservoir's surface will cover . The surface powerhouse, located on the right bank, will contain eight 250 MW Francis turbine generators. There will be eight horse shoe shaped head race tunnels, each being in diameter and having a length from . There will be eight horse Shoe shaped surge tunnels, each being in diameter and having length from . There will be eight horse shoe/circular shaped penstocks with varying diameters of and lengths of. The tail race channel, which will transfer water discharged by the turbines back to the river, is wide and long. Construction Construction of Subansiri Lower Project involves many challenges. These include land not being available when construction was scheduled to commence, a limited annual construction time because of monsoons (from mid-April to mid-October), the need to handle high flood flows and poor rock conditions. The design of the dam has undergone drastic and repeated revisions that have affected the schedule and planning of the construction work. In December 2003 the contract to build the dam and its associated structures was awarded to a consortium of Boguchandgesstroy, Soyuzgidrosptsstry and Soma Enterprise Ltd. Due to difficulties acquiring land around the site, construction could not